scholarly journals Seismic performance of dual systems coupling moment‐resisting and buckling‐restrained braced frames

2020 ◽  
Author(s):  
Fabio Freddi ◽  
Enrico Tubaldi ◽  
Alessandro Zona ◽  
Andrea Dall'Asta
Keyword(s):  
Seismic Performance ◽  
Braced Frames ◽  
Dual Systems ◽  
Moment Resisting ◽  
Buckling Restrained Braced Frames

A Risk-Based Approach to Determine the Optimal Service Life of Steel Buildings in Seismically Active Zones

2013 ◽  
Vol 284-287 ◽  
pp. 1446-1449 ◽  
Author(s):  
Chien Kuo Chiu ◽  
Heui Yung Chang
Keyword(s):  
Service Life ◽  
Braced Frames ◽  
Steel Buildings ◽  
Eccentrically Braced Frames ◽  
Optimal Service ◽  
Probable Maximum Loss ◽  
Moment Resisting ◽  
Structural Fragility ◽  
Active Zones ◽  
Buckling Restrained Braced Frames

The object of this study is to propose, develop and apply a risk-based approach to determine the optimal service life for steel framed buildings in seismically active zones. The proposed framework uses models for seismic hazards, structural fragility and loss functions to estimate the system-wide costs owing to earthquake retrofitting and recovery. With the seismic risk curves (i.e. the expected seismic loss and probability of exceeding the loss), the optimal service life can be determined according to the probable maximum loss (PML) defined by the building’s owner. The risk-based approach is further illustrated by examples of 6- and 20-story steel framed buildings. The buildings have three kinds of different lateral load resisting systems, including moment resisting frames, eccentrically braced frames and buckling restrained braced frames. The results show that for the considered PML (i.e. 40% initial construction cost) and risk acceptance (e.g. 90% reliability), steel braced frames can effectively improve seismic fragility and lengthen service life for a low-rise building. However, the same effects cannot be expected in a high-rise building.

Incremental Dynamic Analysis of Shape Memory Alloy Braced Steel Frames

2014 ◽  
Vol 680 ◽  
pp. 263-266
Author(s):  
Saber Moradi ◽  
M. Shahria Alam
Keyword(s):  
Shape Memory Alloy ◽  
Dynamic Analysis ◽  
Shape Memory ◽  
Seismic Performance ◽  
Steel Frames ◽  
Incremental Dynamic Analysis ◽  
Braced Frames ◽  
Earthquake Excitation ◽  
Uniform Drift ◽  
Buckling Restrained Braced Frames

Incremental Dynamic Analysis (IDA) is a technique to determine the overall seismic performance of structures under varied intensities of earthquakes. In this paper, the seismic performance of four-story steel braced frames equipped with superelastic Shape Memory Alloy (SMA) braces is assessed by performing IDA. The seismic response of SMA-braced frames was compared to that of corresponding Buckling-Restrained Braced Frames (BRBFs). Based on the results of this comparative study, the SMA-braced frames were generally effective in reducing maximum interstory drifts and permanent roof deformations. In addition, the SMA-braced frames demonstrated more uniform drift distribution over the height of the building. As the intensity of earthquake excitation increases, a higher response reduction can be expected for SMA-braced frames.

scholarly journals Damage Concentration Effect of Multistory Buckling-Restrained Braced Frames

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Hanqin Wang ◽  
Yulong Feng ◽  
Jing Wu ◽  
Qing Jiang ◽  
Xun Chong
Keyword(s):  
Statistical Correlation ◽  
Concentration Effect ◽  
Braced Frames ◽  
Braced Frame ◽  
Factors Affecting ◽  
Residual Drift ◽  
Moment Resisting ◽  
Distribution Parameters ◽  
Buckling Restrained Braced Frames ◽  
Parametric Analyses

Due to the low postyield stiffness of buckling-restrained braces (BRBs), multistory buckling-restrained braced frames (BRBFs) subjected to earthquakes are prone to lateral deformations and damage concentrations at certain stories, which is deemed a damage concentration effect (DCE). A series of nonlinear pushover analyses and response history analyses are conducted to investigate the key factors affecting the DCE of BRBFs. Two comparisons of the DCE are performed for different types of structures and different beam-to-column connections in the main frame (MF). These comparisons show that BRBFs equipped with BRBs as the main earthquake resistance system have a more serious DCE than the traditional moment-resisting frame or conventional braced frame and that the MF stiffness significantly affects the structural residual displacement and DCE. Then, parametric analyses are performed to investigate the influence of two stiffness distribution parameters (in the horizontal and vertical directions) on the DCE of a 6-story BRBF dual system designed according to the Chinese seismic code. The results show that increasing the MF stiffness and avoiding abrupt changes in the BRB stiffness between stories can effectively mitigate the DCE of BRBFs. Finally, the correlations between various damage performance indices are analyzed. A low statistical correlation between the peak and residual drift responses can be observed in BRBFs. Therefore, it is recommended that the DCE be considered in BRBF design.

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